Float plug and guide for well casings



June 30, 1931. R. F. HILL FLOAT PLUG AND GUIDE FOR WELL CASINGS Filed April- 23, 1928 2 Sheets-Sheet l INVENTOR June 30, 1931. I 1,811,885

FLOAT PLUG AND GUIDE FOR WELL CASINGS Filed April 23, 1928 2 Sheets-Sheet 2 I I I 11 3:! 5 I 1"; i I: :22; 6 28 2a 12 -17 Z ,13 "1; is if, l| r- 3] If I l l #g 1 L 13 14- 25 55 33 E2 a .J

n t 290. 1 I 17 1;? l I? 39 13 i 4'0 a\|NVENTOR Patented June 30, 1931 UNITED STATES PATENT OFFICE ,ROWLAND F. HILL, TOLEDO, OHIO, ASSIGNOR TO THE NATIONAL SUPPLY COM- PANY, OF TOLEDO, OHIO, A CORPORATION OF OHIO FLOAT PLUG AND GUIDE FOR WELL OASINGS Application filed April 23,

My invention relates to devices by which well casings may be floated and guided down well-holes partially or entirely filled with liquid or with a mud-laden circulating liquid to assist in bringing drillings to the surface of the ground and to cement the walls of the holes to prevent caving.

In lowering strings of casing, where the weight suspended from the derrick is considw erable, it is common practice to utilize the buoyancy effect resulting from displacement of the liquid by the casing which is provided with a float plug and guide at its lower end. When the float plug is used with a guide it is necessary that a hydraulic seal be provided where the float plug is attached to prevent the well fluid from entering the casing along the inner surface of the shoe.

When the casing string is landed at the g bottom of the well-hole, the frangible float plug and guide are broken or drilled up by the drill bit when drilling operations are resumed. It is therefore desirable that the plug and guide be made of brittle material, as cast-iron, which can be readily broken up.

Heretofore float plugs have had either a friction or a threaded engagement with the interior wall of the casing shoe. Those having friction engagement are seldom used because they are not dependable, while those having threadedengagement involve excessive expense making it necessary that the casing shoe be removed from the casing, taken to a shop and threaded, or that all shoes must be provided with threads when manufactured whether or not they are to be used with float plugs.

It is one object of this invention to do away with the threaded connections between the plug and the shoe and provide a more convenient and less expensive manner of connecting the plug to the shoe. Another object is to prevent the well fluid from passing up into the casing between the plug and the casing shoe. Other objects relate to details to be described hereinafter..

Referring to the accompanying drawings, Fig. 1 is a central vertical section through my improved float plug and guide, a portion 51 of the well casing being shown in vertical sec- 1928. Serial No. 272,053.

a transverse section on the line 22 on Fig. 1

Fig. 3,21. central vertical section of a modified form of my invention, parts being in side" elevation and parts being broken away; and Fig. 4, a view of the character shown in Fig. 1, but showin a second modification thereof.

Referring flrst to Figs. 1 and 2, 10 designates a common casing shoe having its upper end internally threaded and receiving the externally threaded lower end of a string of casing, whose bottom length is marked 11. The float plug comprises the sleeve or hollow body 12 carrying at its lower end the valve 13 adapted by upward movement to sit on the annular seat 14 which closes the o ening 15 in the horizontal member 16. e member 16 and the valve 13 when closed prevent any well fluid from passing up into the interior of the body 12. The valve is provided with the vertical stem 17 which is slidable in the boss 18 on the junction of the radial arms 19 whose outer ends are preferably made integral with the body 12. A coiled spring 20 encircles the stem 17 above the boss 18 and hasits lower end seated on the boss and its upper end resting against the washer 21 slidable on the stem 17,. The nut 22 works on the upper end of the stem and down on the washer 21 so that the spring may be held under the expansive power required to seat the valve 13 when it is free to be seated. The valve may be temporarily held from closing by means of the small block 23inserted between the valve and its seat.

A hollow dome-shaped guide 24 has its upper open end screwed on the outer face of the lower end of the body 12. The guide has the opening 25 in its lower or converging end. The upper end of the guide is directly opposite to the lower end of the shoe. I provide a lateral hole 32 in the guide through which a lever 33 may be inserted.

The lower end of the body 12 has pendent cause the packing ring 29 to be compressed so as to prevent t e passage of well fluid into the casing 11 between the shoe 10 and the bod 12. The ring 26, being thick enough to he in both grooves 27 and 28, owing to the shallowness of the groove 28, forms a reactance for permitting the guide to compress the packin ring.

The bo y 12 and the guide having been screwed together, as shown, the upper end of the body, which preferably fits the interior of the shoe 10, is slid into the shoe until the snap-ring 26 in the annular groove 27 in the exterior surface of the body 12 snaps into the groove 28 in the interior surface of the shoe 10 and prevents further longitudinal movement of the body in the shoe. At this time, the upper end of the guide 24 has preferably engaged the packing ring 29 which is then confined by the outer face of the body 12, the downwardly and outwardly inclined lower end of the shoe 10, and the upwardly and outwardly inclined upper end or surface 30 of the guide 24. The surface 30 meets at its upper end the upper end of the downwardly and outwardly inclined surface 31 on the upper end of the guide, the surface 3111 being parallel with the bottom face of the 5 0e.

Without the acking rin 29 liquid laden with grit is lialile to pass t rough the joint between the sleeve and the shoe and sooncauses a large by-pass for the liquid which soon reams out a large hole, thereby making the tool inefiicient and also rapidly destroyin it.

It is common to thread a sleeve into the shoe. The threading of shoes is expensive and particuarly so as all shoes must be threaded under this practice since any shoe in use may require a float plug to be attached thereto. With my invention the shoes need only a simple annular groove which cannot be injured materially by a drilling tool. When the shoes are threaded internally for the attachment of the sleeve, the threads become much damaged or entirely destroyed during the drilling out of a plug and normal drillin operatlons.

with my invention the inner face of the shoe is always ready for the attachment of fresh plugs without any preliminary preparation of the shoes.

A string of casing with the plug and guide and valve as shown in Fig. 1 is lowered into a well hole. The valve may be held open by the block 23 to permit the entrance of a small amount of well fluid while the string is being lowered in order that it will descend at a more rapid rate. However, when greater depths are reached the valve is closed to check the rate of descent of the string, as the weight of the string has been much increased by screwing casing lengths to the top of the string. When it is desired to close the valve, the string may be lifted guickly, causing the valve to lag slightly an thereby releasin the block 23 which drops down the well ho e and permits the spring 20 to close the valve. The string now descends slowly, as the well fluid is displaced and flows up around the shoe 10 and the casing 11.

Fig. 3 differs from Fig. 1 principally in the means used to compress the packing ring after the body 12 has been seated properly in the shoe 10. Instead of inserting a lever through a hole in the guide and engaging therewith pendent lugs on the body, I provide the valve with a horizontal lug 35 which engages'behind the pendent lug 36 on the lower end of the body 12. The center of the lower face of the valve has the wrench head 37 to which a socket wrench may be applied for causing the valve and the body to turn, while the guide 24a is held stationa by means of some gripping or clamping d evice applied to its outer face, or the guide may be turned while the body is held stationary.

The interior face of the guide 24a is provided as shown with dee circular and longitudinal grooves for wea ening the guide so that it may be more easily drilled out.

In Fig. 4 the acking 29a is enclosed by the inner wall 0 the shoe, a shoulder 38 on the body 12a, and a shoulder 39 on the guide 246, extending up between the shoe and the body. In this figure a snap ring 26a having a p circular cross-section is em loyed.

In Fig. 4, the lower end of the body 12a has the yoke or bridge 40 which spans the valve 13 and has at its lower or converging end the wrench head 37a to which a wrench applied through the hole 25 in the guide 24?; may be attached, while the guide is gripped by a suitable device, so that relative rotary movement may be given to the body 12a and the guide 24?) in order to compress the packing 29a.

I claim- 1. In a float plug and guide for well casings, a casing shoe' for attachment to the lower end of a casing, a sleeve positioned within the shoe, means preventing the longitudinal movement of the sleeve in the shoe when the sleeve is in normal position in the shoe, a frangible guide positioned below the shoe and threaded on the sleeve so as to permit the guide to be adjusted toward and away from the shoe, and a packing ring between the shoe and the sleeve and engaged by the guide acting as a gland to compress the packing.

2. n a float plu and guide for well casings, a casing shoe or attachment to the lower end of a casing, a sleeve positioned within the shoe, means preventing the longitudinal the shoe, a packing ring between the shoe and the sleeve and engaged by the guide acting as a gland to compress the packing, and pro vision whereby the sleeve and the guide may a be axially rotated, one with respect to the other to adjust the pressure of the guide against the packing ring.

3. In a float plug and guide for well casings, a casing shoe for attachment to the lower end of a casing, a sleeve positioned within the shoe, means preventing the longitudinal movement of the sleeve in the shoe when the sleeve is in normal position in the shoe, a frangible guide positioned below the shoe and enclosing the lower end of the sleeve and threaded on the sleeve so as to permit the guide to be adjusted toward and away from the shoe, a packing ring between the shoe and the sleeve and engaged by the guide acting as a gland to compress the packing, and provision whereby the sleeve and the guide may be axially rotated, one with re spect to the other to adjust the pressure of the guide against the packing ring, such provision comprising lugs on the sleeve and a hole in the guide through which hole a lever may be inserted to engage the lugs and rotate the guide.

4. In a float plug and guide for well casings, a casing shoe for attachment to the lower end of a casing, a sleevepositioned within the shoe, means preventing the longitudinal movement of the sleeve in the shoe when the sleeve is in normal position in the shoe, a frangible guide positioned below the shoe and enclosing the lower end of the sleeve and threaded on the sleeve so as to permit the guide to be adjusted toward and away from the shoe, a packing ring between the shoe and the sleeve and engaged by the guide acting as a gland to compress the packing,

, shoe and threade and provision whereby the sleeve and theguide may be axially rotated, one with respect to the other to adjust the pressure of the guide against the packin ring, such provision comprising a wrenc -en aging means accessible to a wrench throug in the guide.

5. In a float plug and guide for well casings, a casing shoe for attachment to the lower end of a casing, a sleeve positioned within the shoe, means preventin the longitudinal movement of the sleeve in the shoe when the sleeve is in normal position in the shoe, a frangible (guide positioned below the mit the guide to be adjusted toward and away from the shoe, a horizontal partition in the sleeve, a valve seat in the lower face of the partition, a rotary valve adapted to close the seat, a lug on the valve, a lug on the sleeve en ageable by the first lug to lock the sleeve and the valve against independent rotary movement, and a wrench-engaging means accessible to a wrench through an opening in the bottom of the ide.

6. A frangible oat plug for attachment to the lower end of a casing, the wall of the plug being serrated to form weakened lines to facilitate the drilling out of the plug.

7; A frangible float plug for attachment to the lower'end of a casing, the wall of the plug being serrated to form weakened lines to the lower end of a well casing, a sleeve held within the shoe, a hollow frangible guide carried by the sleeve below the shoe, and a packing ring surrounding the sleeve and engaging the shoe and adjusted by the guide, in combination with means to lock the sleeve from longitudinal travel in the shoe.

In testimony whereof I hereunto aifix my signature.

ROWLAND F. HILL.

an opening n the sleeve so as to per- 

